The present invention relates generally to the field of piezoelectrically driven elements, and in particular, to piezoelectric micromachines used to perform precise tasks or functions.
Certain ceramics, organic polymers and inorganic crystals are known to expand or contract when they are positioned within an electric field at a rate directly proportioned to said electric field. These "piezoelectric" materials will contract or expand depending on the polarity of the applied field. Conversely these materials will also transform a mechanical force into an electrical signal. Thus, if an alternating voltage is applied, periodic variations in the geometry of the material will occur.
When a film of piezoelectric material is secured to a surface of a flexible beam or membrane of appropriate dimension to form a "bimorph" structure, the free portion of the beam or membrane can be made to deflect in a precise and predetermined manner in a direction perpendicular to the plane of the structure. These piezoelectric bimorph structures have been used to perform various functions including operation as transducers, pumps and shutters. Piezoelectric motors, fans and actuators have also been constructed that perform certain types of mechanical functions. The motors utilize piezoelectric driving elements to rotate or translate driven members.